The present invention relates to vacuum treatment systems, and to a vacuum chamber.
EP-0 136 562 discloses a known vacuum treatment system with feeding devices, which are provided on the inner housing and are aligned with the provided treatment chambers and their openings. Radially driven, movable slides serve as driving devices, are mechanically frictionally, synchronously and with the same stroke driven by a central wedge-type drive.
It is a disadvantage in this known approach that it is not possible to design the feed differently for the various provided treatment chambers, as, for example, for meeting different sealing requirements. Furthermore, a respective provided slide must also be actuated when no treatment chamber at all is provided at the opening assigned to it, in that, for example, with the known system, in a flexible manner, a process is to be implemented which requires fewer treatment steps.
Even if, for example, one of the treatment chambers does not require a feeding movement of the workpiece against its opening, as, for example, a heating chamber, a feeding stroke is also carried out there on the known system.
Another major disadvantage of the known system is that the slide stroke movements are wedge-driven. Thus, the stroke is affected by wear. Consequently, workpiece carrier plates are lifted from the carousel against the respective openings and are sealingly placed there against the edge of the opening. Even if the stroke on the known system, as the result of wear, changes only a little, the desired sealing conditions also change, which is intolerable with certain difficult machining processes.
An object of the present invention is to eliminate such disadvantages. Based on a system of vacuum treatment, this object has been achieved by providing that each driving device has a separate drive.
Another object of the present invention is to overcome the wear and sealing problem. Within the scope of the present invention, sealing is effected by a no-contact sealing-off, as by forming a pressure stage by way of a labyrinth seal, as well as a form-locking and/or force-locking sealing.
Because the solution of this problem can also be applied to systems which do not all have the characteristics according to EP-0 136 562, according to a second aspect, the present invention is based on a vacuum treatment system which can be constructed such that a fluid-controlled, preferably pneumatically or hydraulically controlled sealing arrangement is operatively connected wit at least one of the openings, by means of which sealing arrangement a sealing extending around the opening is established and released between the opening bordering and one workpiece receiving device respectively or the workpiece itself.
In this latter aspect, at least one of the openings comprises a fluid-controlled, preferably pneumatically or hydraulically controlled sealing arrangement, or active seal, so that a seal extends around the opening, or is released between the opening edge and a workpiece receiving device or a workpiece itself. As a result, the extent of the seal to be provided can always be advantageously maintained in a constantly uniform manner because, as the result of the pneumatic or hydraulic control, a respectively provided sealing pressure becomes independent of mechanical influences.
One embodiment of the vacuum chamber requires no or only slight lift-off strokes of the workpiece carrier from treatment openings or conveying openings in the wall of the vacuum chamber and is particularly suitable for a use of the above-mentioned active seals.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.